Heat 1 Tbsp. oil in large skillet or wok over high heat. Add meat and stir-fry 1 minute; remove from pan.

Heat remaining 2 Tbsp. oil in same pan. Add broccoli and onion; stir-fry 4 minutes, or until vegetables are tender-crisp. Stir in meat and soy sauce mixture; bring to boil. Cook and stir only until sauce thickens.